SDL2仅绘制整个纹理，而不是像我编码的那样绘制纹理的一部分

Question

出于某种奇怪的原因，每当我尝试将较大的图像文件分割成（在我的情况下）32x32图片时，相反，我得到的整个图片似乎被压缩成32x32（图片整体）。虽然在玩了这些值之后，我意识到由于某种原因，SDL完全忽略了我使用SDL_Rect源（src）的请求。 这意味着我改变源（src）矩形的每个值在运行程序时都不会改变实际图像（即使是一个荒谬的值）。

Sprite.h

#ifndef SPRITE_H_
#define SPRITE_H_

#pragma once
#include "Game.h"

struct Game;

struct Sprite
{
    //Needs to be fixed :/
    //Sprite(const std::string& filepath,int x,int y,int width, int height,Game*game);
    Sprite();
    ~Sprite();
    void Load(const std::string& filepath, int x, int y,int width,int height, Game*game);
    void Draw(Game*game);
    SDL_Rect*getDstRect(){ return &dst; }
    SDL_Rect*getSrcRect(){ return &src; }

private:
    SDL_Surface*surface = NULL;
    SDL_Texture*texture = NULL;
    SDL_Rect src;
    SDL_Rect dst;
    int img_width;
    int img_height;

};

#endif // SPRITE_H_

Sprite.cpp

#include "Sprite.h"

Sprite::Sprite()
{

}

Sprite::~Sprite()
{

    SDL_DestroyTexture(texture);


    surface = NULL;
    texture = NULL;
}

void Sprite::Load(const std::string& filepath, int x, int y, int width, int height, Game*game)
{
    bool success = true;
    surface = IMG_Load(filepath.c_str());
    if (surface == NULL)
    {
        game->getConsole()->Error("SPRITE::Surface Is Not Loaded");
        success = false;
    }
    else
        game->getConsole()->Text("SPRITE::Surface Is Loaded");



    texture = SDL_CreateTextureFromSurface(game->getRenderer(), surface);
    if (texture == NULL)
    {
        game->getConsole()->Error("SPRITE::Texture Is Not Loaded");
        success = false;
    }
    else
        game->getConsole()->Text("SPRITE::Texture is Loaded");



    dst.x = x;
    dst.y = y;
    dst.w = height;
    dst.h = height;


    src.x = 0;
    src.y = 0;
    src.w = 0;
    src.h = 0;

    SDL_QueryTexture(texture, NULL, NULL, &src.w, &src.h);

    SDL_FreeSurface(surface);

    if (success)
        game->getConsole()->Text("Loaded Sprite at " + filepath);
    else
        game->getConsole()->Error("SPRITE::Failed To Load Sprite at " + filepath);

}

void Sprite::Draw(Game*game)
{
    SDL_RenderCopy(game->getRenderer(), texture, &src,&dst);
}

地图类的一部分

testPlayer.Load("bin/sprites/player.png", 200,200,32,32, game);

这是我在弄乱源（src）矩形后尝试更改目标（dst）矩形的值。

Answer 1

https://wiki.libsdl.org/SDL_RenderCopy

dstrect - 目标SDL_Rect结构或整个渲染目标的NULL。 纹理将被拉伸以填充给定的矩形。

短版本 - 调整源矩形以使其与目标矩形具有相同的宽度和高度，并将{x，y}设置为要提取的片段的起始位置。